Wound magnetic core structure for inductive apparatus



1964 F. J. BRUTT ETAL 3,153,214

WOUND MAGNETIC CORE STRUCTURE FOR INDUCTIVE APPARATUS Filed April 26, 1962 2 Sheets-Sheet 1 Fig.2

WITNESSES INVENTORS F erick J. Br 8 M- onso J. Muz ek w ATTORNEY Oct. 13, 1964 F. J. BRUTT ETAL WOUND MAGNETIC CORE STRUCTURE FOR INDUCTIVE APPARATUS 2 Sheets-Sheet 2 Filed April 26, 1962 United States Patent 3,153,214 WWUND hlAGh-IETHJ CFCFRE STRUQTURE l llll ENDUQTHVE APPARATKE Frederick .l. llrutt, Farrell, and Alfonso J. Mazanelr, Hickory Township, Mercer Qounty, Pm, assignors to Westinghouse Electric Qorporation, East Pittsburgh, Pa, a corporation of Pennsylvania Filed Apr. 26, W62, Ser. No. 1%,365 4 Eilaims. Cl. 336-213) This invention relates in general to inductive apparatus, such as transformers, and more particularly to magnetic core structures for such inductive apparatus.

In conventional magnetic core structures for electrical apparatus, such as transformers, a plurality of laminations or punchings is usually formed from magnetic sheet or strip material having a preferred direction of magnetic orientation or easier magnetization substantially parallel to its edges or longitudinal dimension, such as cold rolled silicon steel. The laminations or punchings are then stacked or assembled together to form the diiferent portions of the magnetic core structure required. Magnetic sheet or strip materials have now been developed which have more than one preferred direction of magnetic orientation and which have lower loss characteristics than the singly oriented magnetic materials just described. For example, one type of doubly oriented magnetic strip material which has been developed has a first preferred direction of orientation substantially parallel to its edge or longitudinal dimension and a second preferred direction of orientation substantially perpendicular to its edge or longitudinal dimension. The use of relatively thin magnetic materials of the latter type in conventional magnetic core structures of the stacked type may not be practical due to the difhculties in handling larger laminations or punchings formed from such materials. It is therefore desirable to provide an improved magnetic core structure which utilizes magnetic strip materials which have more than one preferred direction of magnetic orientation and which lend themselves to improved methods of manufacture and assembly.

it is, therefore, a general object of this invention to provide a new and improved magnetic core structure for electrical inductive apparatus, such as transformers.

it is a more particular object of this invention to provide a new and improved low cost magnetic core structure having a leg member that serves as a mandrel for winding the coil.

Briefly, the above cited objects are accomplished by providing a shell member comprising a plurality of laminations of a singly or doubly oriented magnetic material. A ring core member wound from a magnetic strip material having at least one preferred direction of magnetization perpendicular to the direction of rolling of the strip material is fixed in assembled relationship with the shell memher to provide a leg member of the inductive apparatus.

Further objects and advantages of the invention will become apparent as the following description proceeds and features of novelty which characterize the invention will be pointed out in particularity in the claims annexed to and forming a part of this specification.

For a better understanding of the invention, reference may be had to the accompanying drawings in which:

FIG. 1 is a plan view of a shell member made in accordance with this invention;

FIG. 2 is a plan view of a ring core leg member;

FIG. 3 is a top view of FIG. 2;

FIG. 4 is a plan view of a ring core leg member with a coil thereon;

FIG. 5 is a plan view of a core and coil assembly made in accordance with this invention;

3,153,214 Patented Oct. 13., 1964 FIG. 6 is a top view of the core and coil assembly of FIG. 5; and

FIG. 7 shows a core and coil assembly similar to the assembly shown in FIG. 5, except with a plurality of inner leg members.

Referring now to FIG. 1 a plan view of a substantially rectangular shell or leg-yoke member It) is shown. The shell member 16 is wound from a singly or doubly oriented magnetic material having a coating of a suitable insulating material on at least one side, for example, carlite. The shell member lid may be fixed in any convenient manner to prevent unwinding, for example, by banding the completely wound shell member ill, or by placing a coating of adhesive material on one side of the magnetic material to thereby bond each turn to the adjacent turn as the member is being wound. The completely wound shell member is a continuous loop with no joints therein which, of course, greatly reduces the magnetic loss of the apparatus.

()penings l2 and 11 are provided in two sides of the rectangular shell member 19 for the insertion of the leg member tie-rods.

A view of the leg member 14 is shown in FIGS. 2 and 3. The leg member 14 is a plurality of turns 16 of a doubly oriented magnetic strip material. The substantially cylindrical shaped leg member 14 has a hole extending axially therethrough for the insertion of a tie bar. A radial opening Zll extends axially through the leg member 14 to thereby provide a plurality of separate laminations 15 in nested relationship with each other. The radial opening 29) opens the otherwise short circuit to thereby reduce the magnetic losses due to eddy currents. The opening 2%) may be filled with an insulating material such as an epoxy resin to provide further insulation.

PEG. 4 is a View of the leg member 14 with a coil 22 thereon. The leg member 14, similar to the leg member shown in FIG. 2, may be used as a mandrel to wind the coil 22. The coil 22 indicated by the dot dash line of FIG. 4 would have electrical input and output leads 24 thereon.

The leg member 14 and associated coil 22 would be connected in magnetic relationship with a shell member lib similar to that shown in FIG. 1. This assembly is shown in FIG. 5 as a single phase transformer having the leg member 14 fixed in assembled relationship with the shell member it) by a tie bolt 26. The leg member 14 and coil 22 may be assembled with the shell member it) in any convenient manner, for example by bonding or by a tie bolt 26 provided the bolt 26 is from a nonmagnetic material or has the necessary insulating material between the shell and leg members lb and 14 and the tie bolt as. The assembly as shown in FIGS. 5 and 6 is an inexpensive, low loss magnetic core structure. The shell member lil is wound to the shape desired. The leg member l lalso wound to the shape desired has the radial opening cut therein and a coil 22 wound thereon. The leg member 14 with the coil thereon is inserted into the shell member 1b and the tie bolt re placed axially through the leg member. When the nut 28 is tightened on the tie bolt 26 the leg member 14 is fixed securely to the shell member lb. The use of low loss doubly oriented magnetic material for the shell member it) and leg member 14 in addition to the no-joint shell member ill provides a very low loss magnetic core structure for inductive apparatus.

FIG. 6 is a top View of the single phase transformer of FIG. 5 wherein like parts have like reference numbers.

Although the above description describes only a single phase inductive apparatus it is to be understood that multiphase inductive apparatus may be made simply by adding leg members with their associated coil for each phase desired. For example, FIG. 7 shows a three phase inductive apparatus having three leg members 14', 14", and 14" with their associated coils 22, 22, and 22' placed in spaced apart relationship Within a shell member ltl similar to the shell member lb shown in FIG. 5.

While there have been shown and described what are at present considered to be the preferred embodiments of the invention, modifications thereto Will readily occur to those skilled in the art. It is not desired, therefore, that the invention be limited to the specific arrangements shown and described and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

We claim as our invention:

1. A magnetic core structure for electrical inductive apparatus comprising, a shell member Wound from mag netic strip material to form a closed magnetic loop, at least one leg member disposed within the loop formed by said shell member with the ends of said leg member being disposed against said shell member to form butt-type joints, said leg member comprising a plurality of laminations of magnetic strip material disposed in nested re ationship to form a toroidal core section, each of said laminations of said leg member being electrically insulated from the adjacent laminations, said magnetic strip material of said shell and leg members having a first preferred direction of easier magnetization substantially perpendicular to the direction of rolling and a second preferred dire tion of magnetic orientation substantially parallel to the direction of rolling.

2. A magnetic core structure for electrical inductive apparatus comprising, a shell member wound from magnetic strip material to form a closed magnetic loop, at least one leg member disposed within the loop formed by said shell member with the ends of said leg member being disposed against said shell member to form butt-type joints, said leg member comprising a substantially toroidal core section having a radial opening extending axially therethrough to provide a plurality of laminations of magnetic strip material disposed in nested relationship, each of said laminations of said leg member being electrically insulated from the adjacent laminations, said magnetic strip material of said shell and leg members having a first preferred direction of easier magnetization substantially perpendicular to the direction of rolling and a second preferred direction of magnetic orientation substantially parallel to the direction of rollin 3. A magnetic core structure for electric inductive apparatus comprising, a shell member Wound from magnetic strip material to form a closed magnetic loop, at least one leg member disposed Within the loop formed by said shell member with the ends of said leg member being disposed against said shell member to form butt-type joints, said leg member comprising a substantially toroidal core section having a radial opening extending axially therethrough to provide a plurality of laminations of magnetic strip material disposed in nested relationship, said leg member having a coil wound thereon disposed in magnetic relationship with said closed magnetic loop of said shell member, means maintaining said leg member in assembled relationship with said shell member, said magnetic strip material of said shell and leg members having a first pre ferred direction of easier magnetization substantially perpendicular to the direction of rolling and a second preferred direction of magnetic orientation substantially parallel to the direction of rolling.

4. A magnetic core structure for electric inductive apparatus comprising, a shell member wound from magnetic strip material to form a closed magnetic loop, a plurality of leg members each disposed in spaced relation within the loop formed by said shell member with the ends of said leg members being disposed against said shell member to form butt-type joints, each of said leg members comprising a plurality of laminations of magnetic strip material disposed in nested relationship to form a substantially toroidal core section, said toroidal core section having a radial opening extending axially therethrough, each of said laminations of each of said leg members being electrically insulated from the adjacent lamination, said magnetic strip material of said shell member and each of said leg members having a first preferred direction of easier magnetization substantially perpendicular to the direction of rolling and a second preferred direction of magnetic orientation substantially parallel to the direction of rolling.

References (Cited in the file of this patent UNITED STATES PATENTS 

1. A MAGNETIC CORE STRUCTURE FOR ELECTRICAL INDUCTIVE APPARATUS COMPRISING, A SHELL MEMBER WOUND FROM MAGNETIC STRIP MATERIAL TO FORM A CLOSED MAGNETIC LOOP, AT LEAST ONE LEG MEMBER DISPOSED WITHIN THE LOOP FORMED BY SAID SHELL MEMBER WITH THE ENDS OF SAID LEG MEMBER BEING DISPOSED AGAINST SAID SHELL MEMBER TO FORM BUTT-TYPE JOINTS, SAID LEG MEMBER COMPRISING A PLURALITY OF LAMINATIONS OF MAGNETIC STRIP MATERIAL DISPOSED IN NESTED RELATIONSHIP TO FORM A TOROIDAL CORE SECTION, EACH OF SAID LAMINATIONS OF SAID LEG MEMBER BEING ELECTRICALLY INSULATED FROM THE ADJACENT LAMINATIONS, SAID MAGNETIC STRIP MATERIAL OF SAID SHELL AND LEG MEMBERS HAVING A FIRST PREFERRED DIRECTION OF EASIER MAGNETIZATION SUBSTANTIALLY PERPENDICULAR TO THE DIRECTION OF ROLLING AND A SECOND PREFERRED DIRECTION OF MAGNETIC ORIENTATION SUBSTANTIALLY PARALLEL TO THE DIRECTION OF ROLLING. 